1. Field of the Invention
The present invention relates to an electric connector of the circuit board-to-circuit board type on one hand and also relates to a method of making such an electric connector that comprises an insulating housing and two rows of contacts, wherein the respective rows of the contacts are disposed on and along opposite internal surfaces of the housing and at regular intervals.
2. Prior Art
Generally, each row of the contacts built in the prior art connectors of this type will have been united together with a tie ledge before finally treated to give such a finished connector. This is because those contacts are inserted in an injection mold and between an outer section and an inner section thereof, during the so-called insert molding process to form an insulating housing. Subsequently, the tie ledge will be severed from the contacts so that the latter thus becoming discrete from each other within the housing, thereby forming two parallel rows of those contacts arranged at a predetermined pitch along the internal opposite surfaces of said housing.
Those contacts included in each row are very narrow and made of a so thin metallic sheet that the pitch at which they are arranged may sometimes become out of order after having been set in between the outer and inner sections of a mold. Further, they are likely to become bent within the mold. The insulating housing made of a resin is not so sticky to the metal contacts that the latter are protected well from exfoliation apart from and inclination away from the housing""s internal surfaces.
The Japanese Patent Laying-Open Gazette No. 8-31486 discloses one of prior proposals directed to resolution of the described problems. According to this proposal, an upper free end of each contact tapers to engage with a tapered portion that is formed in the outer or inner section of a mold for forming an insulating housing. Such a prior art connector and a method of making it seem effective to avoid any irregularity in the pitch at which the contacts are arranged.
The prior art shown in the Gazette No. 8-31486 could however not contribute to resolve the second problem that the upper portions of the contacts tend to be slanted away from the internal surfaces of the insulating housing.
Therefore, an object of the present invention is to provide an electric connector and a method of making same such that each contact will be secured firmly in the connector at a precise pitch and without any fear of exfoliation from the internal surfaces of its insulating housing.
In order to achieve this object, the present inventor has employed a novel technological feature as summarized below. In this invention, a preamble structure is such that a plurality of contacts are arranged in parallel rows and at a given pitch along internal surfaces of an insulating housing, and each contact has a contacting portion and a solderable lead end, wherein the contacting portion is exposed in the internal surface and the lead end extends outwardly through a bottom of the insulating housing. The characterizing feature of the present connector is that each contact comprises a bent anchoring portion continuing from an upper end of the contacting portion and bent outwardly to reach an external surface of the insulating housing, wherein the bent anchoring portion is embedded in said housing.
Preferably, the bent anchoring portion of each contact may be hook-shaped. The contacting portion of each contact may not be disposed in flush with the internal surface but may protrude therefrom to render the connector more reliable in electrical connection.
A method proposed herein is designed to manufacture electric connectors each having a plurality of contacts that are arranged in parallel rows and at a given pitch along internal surfaces of an insulating housing, with each contact having a contacting portion and a solderable lead end, the method comprising the steps of preparing a mold for forming the insulating housing and consisting of an outer section and an inner section, with the inner section having curved recesses, further preparing a contact assembly that has a tie ledge uniting together the contacts each having a bent anchoring portion continuing from the conducting portion, subsequently placing the contact assembly in between the outer and inner sections of the mold in such a state that the respective bent anchoring portions fit in part in the respective curved recesses, and finally injection molding the insulating housing so that the contacting portions are exposed in the internal surfaces and the solderable lead ends extend outwardly through a bottom of the insulating housing, whereby the bent anchoring portions are embedded in said housing.
The inner section of the mold may have grooves formed therein to fit on the contacting portions of the contacts so that the contacts are more surely held in position at the predetermined pitch during the injection molding, and the contacting portion of each contact is not disposed in flush with the internal surface but protrudes therefrom after the insulating housing has been molded. Each groove may be shaped straight and continue to the curved recess, and thus the word xe2x80x98groovexe2x80x99 is meant herein to include the latter. In this context, the contacting portions in the finished connector will be exposed in the internal surfaces and protrude inwardly therefrom over their full length and partially in the direction of their width, as if they form ridge-shaped protuberances.